Geared power unit



T) G. MYERS GEARED POWER UNIT Sept. 19, 1939.

Filed Jan. 7, 1935 4 Sheets-Sheet l 7770mm? 6? Aye/19 INVENTOR Z4 BY 4TTORNEY g a w W Sept. 19, 1939. MYERS 2,173,339

GEARED POWER UNIT Filed Jan. 7, 19 35 4 Sheets-Sheet 2 A TTORNE y Sept.19, 1939. T. MYERS v 2,173,339

GEARED POWER UNI T 7720010 6. Myers INVENTOR A TTORNEY Sept. 19, 1939.T. e. MYERS 2,173,339

GEARED POWER UNIT Filed Jan. 7, 1935 4 Sheets-Sheet 4 Tho/7706 G. AyersINVENTOR ATTORNEY Patented Sept. 19; 1939 GEARED POWER UNIT Thomas G.Myers, Los Angeles, Calii.'., asslgnor to U. 8,. Electrical Motors,Inc., a corporation of California -Application January 7, 1935, SerialNo. 727

1 Claim.

stallations. The speed at which an alternating current motor operates isa function of the frequency of the power system and of the number ofpoles for which'the motor is wound. Thus where a motor is driven froma-constant frequency, alternating current, source of power supl5 ply,the number of available motor speeds is limited to the number of polesfor which the motor may be wound. For a given power capacity the weightand size of an electric motor increases with the number of poles. It isthus advantageous to employ relatively'high speed electric motors havingfew poles. Consequently the choice of driving speeds which can beobtained economically at the motor shaft is limited. The speed requiredat the load driving shaft is, however,

a function of the connected load and not of the source of power supply.It is therefore advantageous to employ a geared power unit in whichgearing is interposed between the motor shaft and the load drivingshaft.

- It is accordingly an object of this invention to provide anelectrically driven geared power unit,

in'which 'the electric motor may be operated at its optimum speed and inwhich the ratio of the transmission gearing may be varied over a widerange of values to obtain a wide range of speeds at the load drivingshaft.

Fora constant power capacity the torque delivered at the load drivingshaft of the geared power unit varies inversely as the speed of the 40load driving shaft. Consequently, in geared power installations thetorque developed at the load driving shaft may have an extremely largevalue even when motors of relatively low horse P wer capacity areemployed. This torque produ'ces a reactive torque tending to distort thesupporting structure of the gearing and of the driving electric motor.The successful operation and life of transmission gearing are dependenton the ability of the supporting structure to main ta'ln the gearing incorrect power transmitting relation. Distortion of the supportingstructure produces a relative displacement of the gearing members whichprevents the proper mating of the gear teeth, and thereby increases thewear 56 and stress on the gear teeth.

It is accordingly still another object of this invention to provide ageared power unit in which positive and adequate means are provided forsupporting the gearing members, whereby the mating gears are maintainedin accurate align- B ment and at the correct center distance during theoperation of the geared power unit in a power transmitting capacity, andin which the relative locations of the component elements are determinedby means of accurately formed sup- 10 porting surfaces and not by trial.

It is still another object of this invention to provide a geared powerunit in which adequate means are provided for ventilating the drivingelectric motor. 15

It is still another object of this invention to provide adequatelubricating means for the gear members.

In order to provide a compact power unit having a large power capacityin proportion to its 20 weight it is necessary to utilize the maximumpower capacity of the gearing. This requires that the gears be mountedin accurate alignment and at the correct center distance. During themachining of the gear case it is extremely 25 difficult totake-measurements which will establish the positions at which thesupporting surfaces of the bearing structure should be machimed, inorder that the axes of the mating gears will be maintained in correctparallel re- 30 lation. This difficulty may be obviated by soconstructing the geared power unit that a master plate may be employed,on which the gear housing may be supported while it is'being machined.This master plate is provided with means for locating it with respect tothe cutting machine, so that the bearing locating surfaces on thesupported gear housing will be machined at the locations required tomaintain the axes of the mating gears parallel and at the correct centerdistance.

It is accordingly another object of this invention to provide a gearedpower unit in which the bearing locating surfaces of mating gears 45 maybe formed in the required relative position by supporting the gearhousing on a master plate or jig while these surfaces are being formed,and in which the bearing locating surfaces for each of the gear membersmay be formed at a single 5 setting of the/gear housing in the cuttingmachine.

It is still another object of this invention to provide a geared powerunit in which each of the gearing elements together with its supportingmeans may be removed as a unit from the assembly of the geared powerunit.

This invention possesses many other advantages and has other objectswhich may be made more easily apparent from a consideration of severalembodiments of the invention. For this purpose there are shown a fewforms in the drawings accompanying and forming a part of the presentspecification. These forms will now be described in detail, illustratingthe general principles of the invention; but it is to be understood thatthis detailed description is not to be taken in a limiting sense, sincethe scope of the invention is best defined by the appended claim.

Referring to the drawings:

Figure l is a side elevation of a geared power unit incorporating theinvention. This view is partly in section, taken along the axis of themotor shaft, and illustrates the cooperation of the gearing elements,the supporting structure, and the driving electric motor.

Figure 2 is an end elevation of the geared power unit of Figure 1, takenfrom the right hand side with the cover of the gear housing, the loaddriving shaft and the oil slinger removed. This view illustrates theinterior of the gear housing and the means provided for determining thecoaxial relation of the bearing supports of the load driving shaft.

Figure 3 is a detailed view of the motor shaft of the geared power unitof Figure 1, illustrating the means provided for forming the drivingconnection between the motor shaft and the driving gear of the gearedtransmission.

Figure 4 is a side elevation of another. form of the geared power unit.This view is partly in section, taken along the axis of the motor shaft,and illustrates the relation of the gearing elements, the means forrotatably supporting the gears, and the construction of the drivingelectric motor.

Figure 5 is an end elevation of the geared power unit of Figure 4, takenfrom the right hand side, and with the cover of the gear housing and theload driving shaft removed. This view illustrates the bearing locatingsurfaces which are provided for accurately determining the correctcenter distance and the accurate parallel relationship of the axes ofthe mating gears.

Figure 6 is an end elevation, similar to that of Figure 5; but with onlythe cover of the gear housing removed.

Figure 7 is a side elevation of another form of the geared power unit ofFigures 4 to 6.- This view is partly in section, taken along the axis ofthe motor shaft. I

Figure 8 is an end elevation of the geared power unit of Figure '7,taken from the right hand side. 4

' Flgure 9 illustrates the construction of the geared power unit, whichenables the gear locating surfaces to be accurately formed.

Referring to Figure 1: the geared power unit is provided with thedriving electric motor i, having the stator 2, and the rotor 3 mountedon the motor shaft 4. The motor shaft 1 is rotatably supported by .meansof the bearings 5 and 6, which are respectively supported on the endbrackets I and 8. The end bracket 1 may be of a type commonly employedin standard motor construction and may be provided with the downwardlydirected air intake passage 9 and the air deflector ID for the motorventilation. Bearing 5 is supported on and bracket 1 by the bearinghousing H formed by the internal cylindrical surface I2 and theshoulderi3 formed on the end bracket and the bearing cap I4. Toaccurately fix the position of the bearing in the bearing housing, thespacer members I5 may be provided between the bearing and the shoulderl3. By employing several shims for the spacer members IS, the axialposition of the bearing may be fixed within a few thousandths of aninch.

The end bracket 8 is of special construction and together with theremovable cover it form the gear housing H. However, the member 8 may beformed to fit the standard stator dimensions, so that the positions ofthe brackets i and 8 may be changed with respect to the stator 2.Bearing'd is supported on the end bracket 8 within the bearing housing58 formed by the internal cylindrical surface 59 and the shoulder itformed on member 8 and the bearing cap 2 l. The hearing cap 2i issecured to the member 3 by means of screws 22, which pass through thewall of member 8, and which are threaded into the hearing cap 29.

To provide the reduction in speed between the motor shaft and the loaddriving shaft the motor shaft has mounted thereon the driving pinion M,which is in driving relation to the driven gear 25, mounted on the loaddriving shaft. The gears 21-. and 25 may be formed with the helix anglerequired by the gear diameters and the motor speed. The drivingconnection, which is provided between the drivinggear 24 and the motorshaft, will be described in detail in connection with Figure 3.

The load driving shaft 23 is rotatably supported by means of thebearings 26 and 21, which are respectively supported by the internalcylindrical surfaces 28 and 29, formed in the member 8 and in theremovable cover iii of the gear housing. To insure the coaxial relationof the cylindrical surfaces 28 and 29, the'removable cover it is locatedwith respect to the gear housing by the contact of the radial surface 30and the external cylindrical surface 3|, formed on the removable cover,with the radial surface 32 and the internal cylindrical surface 33,formed on the housing member 8. The cover is suitably secured to thehousing by means of the bolts I60 which pass through the cover and arethreaded into the housing member.

By means of the construction provided, lubricant may be easily retainedwithin the gear housing. The contact of the radial surfaces 30 and 32serves to prevent leakage between the cover and the gear housing. Theremovable cover is providedwith the lubricant retaining groove 34adjacent to the load driving shaft and the bearing cap 2! is providedthe lubricant retaining seal 35 for preventing the escape of lubricantinto the motor structure.-

The external cylindrical surface 3|, formed on the removable cover, isformed coaxial with the bearing supporting surface 28 and the internalcylindrical surface 33, on the gear housing, is formed coaxial with thebearing supporting surface 28. Thus by the concentric relation of themating cylindrical surfaces 3! and 33, the cylindrical bearingsupporting surfaces 28 and 28 are accurately and adequately maintainedin coaxial relati'on to positively determine the axis of rotation of theload driving shaft and of the supported gear.

To insure that the cylindrical surfaces 29 and 3| of the removable coverare in fact formed in coaxial relation, these surfaces may be formed ata single setting of the cover IS in a lathe or boring mill, and theradial surfacetfl may be formed at the same time to insure theperpendicular relation of this surface to the cylindrical surfaces. Thecoaxial relation of the cylindrical surfaces 28 and 33, formed on thebearing housing, is best illustrated by Figure 2, which is an end viewtaken from the right hand side of Figure 1 with the cover i6 and theload driving shaft 23 removed. The coaxial relation of the cylindricalsurfaces 28 and 33 may also be insured by forming these surfaces at asingle setting of the gear housing in a lathe or boring mill, at whichtime, the radial surface 32 may also be formed.

To positively fix the position of the driven gear 25 with respect to theload driving shaft 23, the gear is pressed on to the externalcylindrical surface 35 and against the shoulder 31, formed on the loaddriving shaft. A suitable driving connection may be formed between thegear and the load driving-shaft. In the present instance the circularkey 38 is provided, which is secured in a keyway formed in the shaft andwhich engages a keyway formed in the gear. By this construc tion the keyis effectively locked in position and prevented from travelling axiallywith respect to either the gear or the shaft. The bearing. 26 is pressedon to the load driving shaft 23 and against the shoulder 39 formed onthis member. The bearing 21 is likewise pressed on to the load drivingshaft and against the shoulder 40. The axial movement of the shaft andof the associated gear and bearings is limited in one direction by meansof the shoulder 4i formed on the member B, which engages the bearing 26and in the opposite axial direction by means of the shoulder 42, formedon the removable cover, and which engages the bearing 21. In order toaccurately determine the axial position of the load driving shaft,spacer means 43 may be provided between the shoulder 42 formed on theremovable cover and the bearing 21. In this manner the axial position ofthe shaft and of the gear 25 may be limited within a few thousandths ofan inch without the necessity of machining either the housing member 8or the cover to these narrow tolerances.

To provide lubricant for the gears the oil slinger 44 is provided, whichis removably secured to the end 45 of the driving gear. The oil slingermay be suitably held in place by means of the cotter pin 46, whichpasses through the end 45 of the driving gear.

In order to maintain the driving and driven gears in accurate alignmentand at the correct center distance during the operation of the gearedpower unit, means are provided for rigidly securing the housing member 8to the stator, so that the axis of the driving gear 24 is coaxial withthe bore 41 of the stator. To insure the coaxial relation of the drivinggear with the stator, the member 8 is provided with the externalcylindrical surface 48. formed coaxial with the bearing supportingcylindrical surface l9, and which en- 1 gages or mates with the internalcylindrical surface 49, formed on the stator coaxial with the statorbore 41. The axial position of the gear housing with respect to thestator is determined by the contact of the radial surfaces 50 and 5|,formed respectively on the member I and on the stator. Suitable meansmay be provided for maintaining the surfaces 50 and 5| in contact. Inthe present instance bolts 52 are provided, which pass through themember 8 and which are threaded into the stator 2.. ,The bracket memberI which supports, the bearing 5 is also provided with an externalcylindrical surface 53, which engages or mates with the internalcylindrical surface 54 formed on the stator- This member is alsoprovided with the radial surface 55, which engages the radial surface 56formed on the stator.

Toinsure the coaxial relation of the external cylindrical surface 53with the bearing supporting surface l2 and the perpendicular relation ofthe radial surface 55 to these cylindrical surfaces, each of thesesurfaces may be formed at a single setting of the member I in a lathe orboring mill. To insure the coaxial relation of the cylindrical surfaces49 and 54 with the stator bore 41, these surfaces may be formed asfollows: The stator-bore may be first ground to the required diameterand then the stator may be mounted on an arbor which engages the statorbore, afterwhich, the surfaces 48 and 54 as well as the radial surfaces5| and 55 may be formed with the stator so supported. It is thus obviousfrom the construction that the relative position of the driving anddriven gears is accurately determined by the supporting structure, andthat means are provided whereby these gears will be maintained in therequired relative position during the active operation of the gearedpower unit in a power transmitting capacity.

The driving connection formed between the motor shaft and the drivinggear is illustrated by Figure 3. Referring to this figure: The drivinggear 24 is provided with the shank 51, which has an external cylindricalsurface formed thereon coaxial with the gear 24 and which projects intothe chamber 58 formed in the motor shaft. The driving gear 24 isaccurately located in c0- axial relation to the motor shaft by thecontact of the shank 51 with the internal cylindrical surface 59, formedwithin the chamber 58 coaxial with the motor shaft. The diameter of theshank adjacent to the driving gear 24 may be made slightly greater thanthe diameter of the remaining portion of the shank so that a press fitis formed between the end of the motor shaft and the shank 51, therebymaintaining the driving gear in accurate coaxial relation to thesupporting bearing 6, even when the gear is heavily loaded.

To form the driving connection between the pinion shank 51 and the motorshaft, the key I is provided, which engages the keyway 6| formed in themotor shaft and the keyway 52 formed in the pinion shank. The key 60 ispreferably made relatively flat so that the depth of the keyways BI and82 is small in comparison to their width. To form the keyway Si in themotor shaft, thehole 63 may be drilled through the motor shaft into thechamber 58, after which, the keyway 6| may be cut by means of a shapertool which travels between the end of the motor shaft and the hole 63.After the keyway 5| has been formed the hole 63 may be provided with asuitable plug.

The axial position of the driving gear with respect to the motor shaftmay be determined by means of the spacer member 65 interposed betweenthe gear and the end. of the motor shaft. The spacer member 65 alsoserves to maintain the bearing 6 in fixed axial position with respect tothe motor shaft. The member is also provided with a flared portion 66which projects almost to the shoulder 20, thereby preventing theentrance of excessive lubricant into the bearing housing. To precludethe possibility of lubricant accumulating within the bearing housing andthereby escaping along the motor shaft'into the motor structure, the oilreturning grooves 51 are provided on the internal periphery of thebearing housing. The oil returning grooves 61 conduct the lubricantpast'the bearing to the holes 68, through which the lubricant'isreturned to the gear housing. As illustrated by Flgure 2, a plurality ofthe grooves 61 and holes 68 may be provided, so that the lubricant maybe returned to the gear housing irrespective of the particular positionin which the geared power unit is mounted. I

In order to prevent the pinion shank from pulling away from the motorshaft the pinion shank is provided with the conical shoulder. 88 and themotor shaft is threaded to engage the set screw 10, which passes throughthe motor shaft and which engages the conical head 68 of the pinionshank. As the set screw 18 is screwed into position the head of thescrew urges the conical shoulder 68 and the pinion shank in an axialdirection to draw the pinion shank farther intothe motorshaft, therebybringing spacer member 85 into contact with the bearing 6 mounted on theend of the motor shaft and thus accurately fixing the'axial position ofthe pin! ion. In order to remove the pinion from the motor shaft, theset screw 18 may be withdrawn and the pinion shank may then be drivenout of the chamber 88 by means of a suitable rod inserted throughpassage II from the opposite end of the motor shaft.

The construction illustrated by Figure 3 may be employed with drivinggears having a diameter slightly less than that .of the internalcylindrical surface i8 of the bearing housing, as it is necessary toinsert the driving gear into the gear housing through the cylindricalsurface i9, if it is desired toform the connection between the drivinggear 24 and the motor shaft 4 external of the geared power unit. In thatcase the assembly of the geared power unit may take place as follows:The housing member 8 may first be secured to the stator, after which,the rotor, the motor shaft, and the driving pinion may be inserted intoplace through the stator bore from the opposite end of the stator. Thebearing cap 2| and the bracket member I may then be secured in position.The load driving shaft together with the driven gear and the supportingbearings may then be inserted in to position'through the apertureprovided by the removable cover l8, as illustrated by Figure 2. The ,oilslinger 48 may then be secured to the end of the driving gear, afterwhich, the removable cover I6 may be secured into position. v

If it is desired to employ a driving gear having a diameter greater thanthat of the bearing 8, the driving gear 24 may be mounted on anextending portion of the motor shaft in the same manner as the drivengear 28 is mounted on the load drivi 8 shaft. It is obvious from theconstruction, as

' illustrated by Figure 2, that the diameters of the driving and drivengears may be varied between wide limits to obtain the required speed atthe load driving shaft; as the aperture provided by the removable coverI 6 provides means whereby the gears may be inserted in positionirrespective of whether the driving or the driven gear has the greaterdiameter,

As has been previously noted, the bracket memh 1. Figure 1. is providedwith the air intake passage 8 and the air deflector l8. The housingmember 8 is likewise provided with the 'air intake passage 12 and theair deflector I8. To produce the motor ventilation the rotor 8 isprovided with which draw air into the motor structure through I the airpassages and air deflectors formed in members l and 8. The airis'directed by the fans I4 over the stator winding .15 and into the airpassage 18 formed between the external periphery of the statorlaminations I1 and the removable stator cover I8. The air passes overthe stator lamination along the passage 18 and is discharged from themotor structure at either side of the stator through the air dischargepassage 18, formed between the removable cover, 18 and the stator feet,as well as through the downwardly directed air discharge passages 88formed in the removable cover 18. By means of this construction themotor is protected against falling liquid, as the air intake passagesaswell as the air discharge passages are formed with downwardly directedopenings. The construction provided is of particular utility as air isdrawn in from both ends of the motor structure and discharged at thecenter, thereby maintaining the lowest possible operating temperaturewithin the motor structure as well as within the gear housing.

Figures 4 to 6 illustrate another form of the geared power unit ofFigure 1. In this form means are provided forobtaining an increasedreduction inspeed between the motor shaft and the load driving shaft.The construction of Figures 4 to 6 may be the same as that of Figures 1to 3 except for the differences which will be noted. In the form ofFigure 4 the motor shaft, and housing member 8 of Figure 1 are replacedby the motor shaft 8| and the housing member 82, which together with theremovable cover 88 forms the gear housing 84. The housing member 82 maybe supported on the stator 2-in the same manner as the housing member 8of Figures 1 to 3. I Thus the member "is-provided with the externalcylindrical surface 85 and the radial surface 88 which correspond to theexternal cylindrical surface 48 and the radial surface 80 of the member8. The housing member 82 is secured to the stator by means of the boltsI88, which pass through the member 82- and which are threaded into thestator. A plurality of the bolts I88 may be provided so that the angularposition of the sear housing can be changed with respect to the statorto provide difi'erentangular positions of the load driving shaft withrespect to the motor frame.

The member 82 is also provided with the im temal cylindrical surface 81,formed coaxial with the cylindrical surface 85, and which forms asupport for the bearing 88, which displaces the bearing 8 of Figure 1.To provide a bearing having an increased capacity for radial load and asmall external diameter a double row'bearing may be employed for thebearing 88. The member 82 is also provided with the air intake passage88 and the air deflector 88 for the motor ventilation.

The motor shaft 8i is in coaxial driving relation to the driving pinion8i, which drives the driven gear 82, mounted on the load driving shaft88. In this form the bearing 88 is mounted directly on the shank 84 ofthe driving pinion and is held in place between the shoulder 88, formedon the pinionsh'ank, and the end of the motor shaft. The shank of thedriving pinion projects into the cylindrical chamber 88 formed in theend of the motor-shaft. and is provided with the portion 81, having anexternal cylindrical surface of slightly greater diameter than theremaining portion of the shankrwhich engages the internal surface ofthec'ylindrical chamber 88 to form a press fit between the pinion shankand the motor shaft. The portion 01 of increased diameter is preferablyof .relatively short length so that although the motor shaft ismaintained in accurate coaxial relation to the bearing 88, nevertheless,the driving pinion is not rigidly fixed in angular position by this fit;but is free to move through a small angle if necessary. The drivingpinion is held in place by means of the set screw 98, which passesthrough the motor shaft and which engages the conical'shoulder 80 formedon the pinion shankto urge the pinion shank farther into the cylindricalchamber 06. The driving connection between the motor shaft and thepinion shank is formed by the key I00 which is similar to the key 60 ofFigure 3.

The bearing 88 is axially fixed with respect to the member 82 by meansof the bearing caps IM and I02. The bearing cap I02 also serves toprevent the entrance of excessive lubricant intothe bearing housing, forthis purpose the bearing cap is provided with the extending lip I03which comes almost into contact with the pinion. The bearing caps IN andI02 are held to the housing member 82 by means of screws I04, which passthrough the bearing cap I02 and the member 82, and which are threadedinto the bearing cap I0 I In order to prevent lubricant fromaccumulating within the bearing housing, lubricant returning passagesI05 are provided, which return the lubricant to the gear housing. Asillustrated by Figure 5, a plurality of these passages may be providedfor returning the lubricant to the gear housing irrespective of theparticular position in which the geared power unit is mounted.

In addition to the bearing 88, the pinion is provided with the bearingI06 for supporting the other end of the pinion. The bearing I08 isremovably mounted on the cylindrical surface I01 of the pinion and isheld in place between the locknut I08 and the shoulder I00 formed on thepinion, the oil slinger I I0 and the collar II I being interposedbetween the bearing and the shoulder I09. The axial position of themotor shaft and of the pinion is fixed by the bearings 5 and 88, thusthe bearing I00 has to be supported only for a radial load. To providethis support bearing I06 is supported by the internal cylindricalsurface II2 formed on the-removable bearing supporting plate H3. Thebearing supporting plate H3 is in turn supported on the member 82 by theengagement of the external cylindrical surface I I4, formed on the platecoaxial with the internal cylindrical surface II2, with theinternalcylindrical surface II5, formed on the housing member 82. The axialposition of the bearing supporting plate is determined by the contact ofthe radial surface IIB, formed on the member II3, with the radialsurface I I1 formed on the member 82. The internal cylindrical surfaceH5 is formed coaxial with the cylindrical surfaces 85 and 81, therebysupporting the pinion coaxial with the motorshaft. The coaxial relationof the cylindrical surface I I5 with the pinion is best illustrated byFigure 5, which is a view of the interior of the gear housing with theload driving shaft and the bearing supporting plate II3 removed.

'The means provided for securing the bearing supporting plate I I3 tothe housing member 82 is best illustrated by Figure 6, which is a viewof the interior of the gear housing with only the cover 83 removed. Theplate H31 is secured to the member 82 by the screws I I8, which passthrough the ears N0 of. the plate 8, and which are threaded into themember 82.

The driven gear 92 is pressed on to the cylindrical surface I20 formedon the load driving shaft and against the shoulder I2I, the key I22being provided to form the driving connection between the gear and theload driving shaft. The load driving shaft is rotatably supported by thebearings I23 and I24, which are respectively supported by thecylindrical surfaces I25 and I26 formed on the member 82 and theremovable cover 83. The cylindrical bearing supporting surface I26 issupported in coaxial relation to the bearing supporting surface I25 bythe engagement of the external cylindrical surface I21, formed on theremovable cover, with internal cylindrical surface I28, formed on thehousing member 82, the mating cylindrical surfaces I21 and I28 beingrespectively formed coaxial with the cylindrical surfaces I25 and I25.The coaxial relation of the cylindrical surface I 28 with the bearingsupporting surface I25 is best illustrated by Figure 5.

The axial position of the removable cover is determined by the contactof the radial surface I29, formed on the cover, with the radial surfaceII1, formed on the housing, the cover being secufed to the housing bymeans of bolts I30, which pass through the cover and which are threadedinto the housing member. The contact of the radial surfaces I29 and H1serves to prevent leakage of the lubricant from thegear housing. Thebearing cap IOI is provided with the lubricant retaining seal I3I toprevent the escape of the lubricant into the motor structure and theremovable cover 83' has the lubricant returning passages I32 formedtherein for returning theillustrated by Figure 6. Referring to Figure 6;l

it is obvious that the removal of cover 83 gives' access to the screwsII8 which hold the bearing supporting plate II3 to the flange formingthe surface H1. The bearing supporting plate may be removed by removingthe screws II 8, after which the locknut I08 may be removed to permitthe withdrawal of the oil slinger H0 and the collar III. With thesemembers removed; the load driving shaft together with the driven gear 92and the supporting bearings I23 and I24 may be removed through theaperture provided by the internal cylindrical surface I28, thus leavingonly the driving pinion 9I in the gear housing, as illustrated by Figure5. To remove the driving pinion 9|, it is only necessary to remove thescrews I04, which hold the bearing caps IOI and I02 in place, afterwhich, the driving gear together with the rotor and the motor shaft thegeared power unit of Figures 4 to 6. Figure 7 is a side elevation ofpower unit and Figure 8 is an end view taken from the right hand side ofFigure 7. The geared power unit of Figures '1 and 8 may be of the sameform as that of Figures 4 to 6 except for the differences which will benoted. In this form the housing member 82 of Figure 4 is replaced by thehousing member I34, which also forms a common support for the gearhousing and for the driving motor. For this purpose the housing I34 isprovided with feet I35, which project beneath the load driving shaft,and with the feet I36 which project under the driving motor I44. Thusthe housing member I34 forms a pyramid type of support for the entireunit. In this form the stator 2 of Figures 1 to 6 is replaced by thestator I31, which is provided with the internal cylindrical surface I38and the radial surfaces I39, which are similar to the internalcylindrical surface 49 and the radial surface I of the stator of Figures1 to 6. The motor may also be provided with the end bracket I, the rotor3, and the motor shaft 8|,

which are of the same form as those of Figure 4.

However, the removable stator cover I8 is replaced by theremovable'stator cover I40, which may enclose the entire periphery ofthe stator. Thus in this form the motor ventilation may be maintained bymeans of the ventilating passages provided in the end brackets I, and bythe air intake passage I, the air deflector I42, and theair dischargepassage I43, formed in the member I34. Thus by means of the constructionprovided the motor is both drip-proof and splash-proof.

The motor I44 is'supported on the housing member I34 by the engagementor mating of the'internal cylindrical surface I38 and the radial surfaceI39, formed on the stator, with the external cylindrical surface I45 andthe radial surface I46, formed on the housing member I34. These surfacesmay in every way be identical with the corresponding surfaces 85' and860i member 82 of- Figures 4 to 6. The stator is suitably secured to thesupporting member by means of the bolts I41, which pass through thesupporting member and which are threaded into the stator. The supportingmember I34 together with the removable cover 83 form the gear housingI48, in which are supported the driving gear 9I and the driven gear 92,which may in every way be similar to the corresponding gears of Figures4 to 6. Likewise, the driving gear and the motor shaft may be rotatablysupported by means of the bearings 38 and I06 as in Figure 4. The loaddriving shaft 93 may also be rotatably supported by the bearings I28 andI24. The removable cover may be suitably secured to the,

drive on the load driving extension I52 of the load driving shaft. orchain drives of this type produce a torque on the load driving shafttending to rotate the entire structure of the geared power unit, as wellas a direct radial pull on the shaft which tends to twist the gearedpower unit on its supporting feet. By means of the strong supportprovided by the feet I35 and I36 of the supporting housing, the gearedpower unit may be rigidly supported adjacent to the load driving shaft,thereby decreasing the reactive torque applied to the frame of thegeared power unit, as well as removing the resultant stress from themotor structure, which in the case oi. general purpose electric motorsthe motor is not designed to withstand.

Figure8 is an end view of the geared power unit of Figure 7,'taken fromthe right hand side of Figure 7, and illustrates the rigid supportprovided for the geared power unit by the supporting structure. The feetare well spread and thus reduce to a minimum the stress transmitted tothe supporting foundation. This view also illustrates the means providedfor replenishing the supply of lubricant within the gear housing. Forthis purpose the removable pipe plug I53 is provided, which is threadedinto the member I34 to provide a lubricant intake passage to the gearhousing. To provide means for draining the used lubricant from the gearhousing, the drain plug, I54 is provided at the bottom of the gearhousing.

It has been stated to be an object of this invention to provide a gearedpower unit in which the bearing locating surfaces for each ofthe gearmembers may be formed at a single setting of the gear housing in theproper cutting machine, and in which the surfaces determining therelative locations of the mating gears may be accurately formed in therequired relative positions without the necessity of taking measurementson the gear housing during the forming of these surfaces. The manner inwhich this object may be accomplished is illustrated by Figure 9, whichillustrates in particular how the bearing locating surfaces of thehousing member 82, of Figure 4, may be formed. The member 82 is firstset up in a lathe or boring mill and has the stator engaging surfaces 85and 86 formed thereon. This process may be repeated on as many of thehousings as it is desired to machine in a single group. Either thesurfaces I25 and I28 which determine the location of the driven gear, orthe surfaces 81 and II5 which determine the location of the driving gearmay be formed next. To form these surfaces the housing member '82 issupported on the master plate. or jig I55, and is located with respectto this plate by the engagement of the cylindrical surface 85 and theradial surface 86 respectively with the cylindrical surface I56 and theradial surface I 51,

formed on the plate. The surfaces I58 and I51, I

. I59 is exactly equal to the required center distance member 82 is thensupported on the plate I55, as

illustrated, and is suitably secured in any desired manner, eitherdirectly to the rotating head of the machine, or to jig I55. It isobvious that with the member 02 so supported, each of the radialsurfaces, formed on the member, will be formed parallel to the radialsurface 86 and that each of the cylindrical surfaces machined with thisset up will be formed coaxial with the cylindrical surface 85. Thus thecylindrical surfaces 81 and H5 may be formed to the required diameterswith the positive assurance that they are located in the requiredcoaxial relation with the cylindrical surface 85. The plate I55 may beleft located in this position until the surfaces 81 and 5 have beenformed on all of the housings in the group. 7

After this machining operation is completed,

' the housing 32 is removed and the plate I55 may then be moved to theposition at which the axis of rotation of the machine is coaxial thecylindrical pin I58 and perpendicular to the radial surface I51. Thehousing member may then again be supported on the plate, as illustrated,and may be rotated with respect to the plate I55 so that those parts ofmember 82 which are now to be machined will overlie the pin I59. Thehousing member may then be secured to the rotating head of the cuttingmachine in this position. The cylindrical surfaces I25 and In may thenbe formed to the required diameters and the radial surface I" may beformed at the required distance from the radial surfaces 86 and I51. Asplate I55 was positioned in the cutting machine so that the surfaces cutwould be conhave centric with pin I58 and perpendicular to surface I51,the driven gear will be located positively by these surfaces with itsaxis parallel to and at the correct center distance from the axis of thedriving gear. The plate I55 may be left supported in this position untilthe machining of all of the housings in the group is finished.

It is thus obvious that the difficult and uncertain measurementscommonly associated with the construction of gear housings are obviatedby means of the construction disclosed. The housing member 134 ofFigures 7 and 8 may be machined in the manner illustrated by Figure 9.The housing member 8 of Figures 1 to 3, may the locating surfaces is, 48and 50 formed at a single setting of the member in a lathe or boringmill, after which the surfaces 28, 32, and 33 may be formed with themember supported on a master plate in the manner illustrated by Figure Iclaim:

In a geared power unit, a motor having a frame and a shaft, a loaddriving shaft,-means forming a gear transmission for transmitting powerfrom the motor shaft to the load driving shaft, a hous ing for saidtransmission, and secured to the frame of the motor, means in saidhousing forming an air intake passage to said motor, and means in saidhousing permitting air to be discharged from said motor.

.'I'HOMAS G. MYERS.

